Bussie Maziya-Dixon, Antonio Montes-Lopez, Oladeji Alamu, Ibironke Popoola and

Robert Asiedu

Enhancing the Role of Yam in Food Diversification and Income Generation

As much as 97 percent of the increase in world population from 2000 to 2050 will occur in today’s developing countries.

The developed countries’ share of population is expected to fall from 20 percent in 2000 to only 13 percent in 2050.

Africa will undergo the most rapid growth, increasing from 784 million in 2000 to nearly 1.8 billion in 2050.

Introduction

The food industry in West and Central Africa

Globally, urban areas are currently growing at a rate of 2.2 percent

Rural to urban migration is the most significant and relevant trend from the point of view of the food processing industry.

Therefore, there is a strong local demand for transformed products which would meet the rising standards in terms of quality, sanitary and nutritional requirements.

More than 54 million tons of yams are produced in Sub-Saharan Africa annually

Over 95% of this production lies in a five-country “yam belt” that includes Nigeria, Benin, Togo, Ghana, and Côte d'Ivoire, with Nigeria as the leading producer.

Importance of Yams

Plays a key role in food security based on the range of species, maturity periods of cultivars, superior shelf life of fresh tubers compared to other root and tuber crops

Yam is consumed in different ways, such as boiled, fried, or baked.

Tubers are often dried and milled into flour for reconstituting into a stiff paste, which is eaten with soup.

Importance of Yams

Importance of Yams

Yam is suggested to have nutritional superiority when compared with other tropical root crops

It contains some amount of proteins, lipids, vitamins and minerals

Modern researches have shown that yam extracts can

-reduce blood sugar

-show antioxidative activity

Quality is a combination of product properties or attributes which can play a crucial role in defining end user acceptability

Properties considered:

a) Organoleptic and sensory attributes

b) Safety

c) Nutritional value

d) Functional properties

e) Stability during storage

Quality Characteristics (Food quality/end-user attributes)

Functional properties are important food quality characteristics that have impact on consumer product acceptability.

They can also be used as indicators or determinants of food quality for yam-based food products.

Varieties with good eating qualities are characterized by high dry matter; starch and amylose content.

To stimulate demand, research for development must understand and encourage the demand for yam products.

Importance of Quality Characteristics

Proximate composition of selected white yam varieties grown in riverine areas( N=12)

%Dry matter 36.3%Ash 1.98

%Protein 2.91%Fat 1.2

%Sugar 3.36

%Starch 56.7

%Carbohydrate 30.2

%Amylose 29.3

Vitamin C, anti-nutritional factors and Functional properties of selected white yam varieties grown in riverine areas(N=12)

Swelling Power 8.09

Solubility(%)

6.83

Water Binding Capacity (%) 129

Vitamin C (mg/100g) 6.49

Phytate(mg/100g) 18.2

Tannin(mg/100g) 7.1

MC Ash Fat Protein Sugar Starch Amylose

9.12

2.720.54

7.18

1.05

33.7

18.59

5.41

1.980.600000000000001

5.6

0.630000000000002

31.78

20.3

Proximate Composition (%)( N=40)

GhanaNigeria

Perc

ent

Comparative analysis of nutritional qualities of white yam varieties from Nigeria and Ghana

Vitamin C and anti-nutritional factors of white yam varieties grown in Ghana and Nigeria

Phytate (%)

Tannin(%)

Vit C(mg/100g)

Location Ghana Nigeria Ghana Nigeria Ghana Nigeria

Mean 2.11 2.63* 0.12 0.22* 7.48* 5.13

Minimum 1.38 2.04 0.04 0.07 4.90 2.89

Maximum 3.71 3.30 0.18 0.32 10.00 6.68Std. Deviation 0.68 0.30 0.04 0.08 1.64 1.32

* Difference significant at 0.05

Objective: Delivering highly consumer accepted varieties and linking farmers to markets and food industry.

Selection of D. rotundata varieties to produce yam flour (IITA-DELUXE)

Methodology1. Elite varieties from AYT and were

selected released varieties .2. Testing varieties with yam

processors3. Determining processing

parameters4. Selection by processors, assisted

by quantitative data elicited during the processing in their factory.

Parameters measured:1. Fresh weight2. Weight after peeling3. Conversion rate

Fresh/Flour4. Cooking time5. Sensory attributes

Results

Dioscorea rotundata varieties selected for yam flour-instant poundo yam

TDr 89/0

2665

TDr Am

ula

TDr Alu

maco

TDr 07/0

0983

TDr 07/0

0362

TDr Om

i-efu

n

TDr 07/0

0777

TDr 07/0

0314

TDr 05/0

0570

TDr 02/0

0515

TDr Ehobia

TDr 03/0

0180

TDr 00/0

0403

TDr M2/5

0/7

TDr 05/0

1019

TDr 00/0

0362

TDr 95/1

9158

TDr 01/0

04050

0.5

1

1.5

2

2.5

3

3.5

4

4.5

Kg

FR

ES

H :

1 K

g F

LO

UR

Threshold 1 (4varieties)

Threshold 2(4varieties )

Methodology

Materials and methods1. Elite and released

varieties selected 2. Testing varieties with

yam processors3. Measuring processing

parameters4. Selection by processors,

assisted by quantitative data elicited during the processing in their factory.

Parameters measured1. Fresh weight2. Weight after peeling3. Oxidation4. Blanching5. Freezing6. Frying7. Sensory attributes8. Selection Index

Selection of D. rotundata and D. alata varieties to produce yam fries: (IITA, PRIMLAKS-SIMPLI)

Result

Selection index: Processors+Breeder+ConsumerS

elec

tio

n I

nd

ex (

SI)

6 7 9 10 13 15 17 18 19 20 21 22 33 44 550

0.5

1

1.5

2

2.5

3

3.5

4

Variety

CH 2: Commercial Potato French fries CH 1 : Commercial yam fries

CH 1CH 2CH 1

Threshold of selection

Variety 6,10,13,17,20,22 and also 9 and 15 were selected

Diversification of yam utilization through product development using D. Alata

- Degree and non degree training

- Training of Trainers

- Demand-driven processing workshops

Capacity building and technology dissemination through training

Summary• Yam plays a key role in food security

• Selection and identification of varieties with good eating qualities with high dry matter; starch and amylose content are being selected ( Nigeria and Ghana)

• Selection and identification of varieties that are good for instant poundo- yam and yam fries

• Diversification of yam utilization through product development – yam cake, yam fritters, yam flakes, yam bread etc

• Dissemination of technology through training ( Train the trainers, processing workshops etc)

Next Steps:

Product Development and characterization

Technology dissemination through training

Sensory Evaluation GIS-Areas to produce each

variety Linking Farmers

Acknowledgement

THANK YOU